The present invention relates to a method and apparatus for statically or dynamically determining the weight of a railway supported vehicle. The present invention is believed to provide a method and apparatus which are particularly advantageous for weighing rail supported vehicles which carry material such as molten metal which is often subject to spillage, and which material can do substantial damage to elements of a weighing system when it comes into contact therewith.
Railway supported vehicles known as torpedo cars are often used to transport molten metal from an open hearth furnace to a basic oxygen furnace. Such torpedo cars are generally very long and are designed to support great weights of molten metal. During filling and movement of the vehicle there is often considerable spillage of molten metal onto the railway structure. Such molten metal can, and does, do considerable damage to the railway structure. Damage caused by molten metal often requires replacement of the standard ties or sleepers which support the rails, and can also necessitate replacement of sections of the rails themselves. Where vehicle weighing systems are involved, such problems may be even more acute, because the systems often include highly sensitive portions which can be damaged by molten material more quickly than standard railway support structure.
One type of weighing system which is particularly suitable for weighing vehicles such as torpedo cars is disclosed in U.S. application Ser. No. 730,074, filed Oct. 6, 1976, now Pat. No. 4,036,315. According to this disclosure the weighing system includes pairs of weighing platforms which replace portions of the rails. The pairs of platforms are spaced apart along the length of the rails by a distance which is equal to the distance between the forward and rear axles of the torpedo car. The size and spacing of the weighing platforms are such that one weighing platform engages the wheels supported on a fraction of the axles at the forward end of the torpedo car and the other weighing platform engages the wheels supported on a fraction of the axles at the rear end of the torpedo car. Respective foundations are provided for supporting the wheels which are not in contact with the weighing platforms. Interposed between the respective platforms and the foundation are load cells which provide signals which vary as a function of the load applied to the platform and, the signals from the load cells are electrically processed to provide an indication of the total weight of the load carried by the torpedo car. In the foregoing, problems due to spillage are minimized because the platforms are small enough to support only a fraction of the wheels of each end of the car, and because the platforms are spaced apart by a considerable distance due to the overall length of the torpedo car.
In the art there have also been numerous other types of railway vehicle weighing devices disclosed, though not necessarily directed specifically toward weighing torpedo cars. For example, various disclosures of weighing devices can be found in the form of platforms which are intended to effectively replace sections of the rails for supporting the railway vehicle wheels. Such types of devices can be found in disclosures such as U.S. Pat. Nos. 3,714,997 and 3,734,217. Still other examples of railway vehicle weighing devices include weigh rails which replace a portion of the standard rails. Such type of vehicle weighing devices can be found in disclosures such as U.S. Pat. Nos. 3,734,216, 3,741,327 and 3,747,715.
In addition, other types of prior art railway vehicle weighing devices can be found in disclosures such as U.S. Pat. Nos. 3,004,152, 3,085,642 and 3,159,227; British Pat. Nos. 820,969, 797,161, and 832,389; German Pat. No. DBP/1,079,338; French Pat. Nos. 1,292,587 and 974, 974; and Swedish Pat. No. 217,810.